The instant invention provides substituted 3-alkyl-5-isopropyl cyclohexenones a number of which are novel, defined according to the structure: ##STR2## wherein one of the dashed lines represents a carbon-carbon double bond and the other of the dashed lines represents a carbon-carbon single bond; wherein R.sub.4 represents methyl or ethyl; wherein one of R.sub.1, R.sub.2 or R.sub.3 represents 2-methyl-1-propenyl or 2-methyl-1-propylidenyl and other of R.sub.1, R.sub.2 and R.sub.3 represents hydrogen; with the provisos that:
(i) when the dashed line at the 3-4 position is a double bond, R.sub.3 is hydrogen or 2-methyl-1-propenyl; PA1 (ii) when the dashed line at the 2-3 position is a double bond, R.sub.2 is hydrogen, methyl or 2-methyl-1-propenyl; PA1 (iii) when R.sub.4 is ethyl, then R.sub.2 is methyl and the double bond is at the 2-3 position; and PA1 (iv) when R.sub.4 is methyl, when R.sub.2 is hydrogen; 2-methyl-1-propenyl or 2-methyl-1-propylidenyl; PA1 (i) Wiemann, et al, Ann. Chim., 1972, Volume 7, pages 399-499, title: "Contributions a L'Etude des Mechanismes de Condensations Catalytiques de Cetones .beta.-Alkyl .alpha.-Ethyleniques en Milieu Heterogene et en Phase Vapeur. Etudes Spectrographiques IR, UV, RMN". PA1 (ii) Riand and Brun, Bulletin de la Societe Chimique de France, 1976, Nos. 3-4 (combined) pages 557-562 inclusive, title: "No. 105--Spectrometrie de Masse. II--Fragmentations Induites par Impact Electronique de Cyclohexenones".
with the members of said genus being novel compounds when R.sub.4 is ethyl or when R.sub.4 is methyl and the double bond is at the 3-4 position or when R.sub.4 is methyl and the double bond is at the 2-3 position with R.sub.3 being hydrogen.
Chemical compounds which can provide peppery, sweaty, guiacwood-like, green, burnt grass, vetiver-like, sandalwood-like, fresh, floral, citrusy and spicy aroma nuances with sauge sclaree topnotes and musky undertones are highly desirable in the art of perfumery. Many of the natural materials which provide such fragrances and contribute such desired nuances to perfumery compositions are high in cost, unobtainable at times, vary in quality from one batch to another and/or are generally subject to the usual variations of natural products.
By the same token, materials which can provide woody, peppery and citrusy aroma and taste nuances in smoking tobacco compositions and smoking tobacco article components prior to smoking and can impart a sweet, citrusy character to smoke flavor in smoking tobacco compositions and smoking tobacco articles on smoking are highly desirable in the art of smoking tobacco flavoring. Many of the natural materials which provide such aroma and taste nuances are high in cost, unobtainable at times, vary in quality from one batch to another and/or are generally subject to the usual variations of natural products.
There is, accordingly, a continuing effort to find synthetic materials which will replace, enhance, or augment the essential flavor and fragrance notes provided by natural essential oils or compositions thereof.
The fundamental problem in creating artificial flavor and fragrance agents is that the artificial flavor or fragrance to be achieved be as natural as possible. This generally proves to be a difficult task since the mechanism for flavor and/or fragrance development in many fragrance materials and tobacco products is not completely known. This is noticeable in products in the fragrance area having peppery, sweaty, guiacwood-like, green, burnt grass, vetiver-like, sandalwood-like, fresh, floral, citrusy and spicy aroma nuances with sauge sclaree topnotes and musky undertones and in the tobacco area for materials which provide woody, peppery and citrusy aroma and taste nuances to smoking tobacco prior to smoking and imparts a sweet, citrusy character to smoke flavor on smoking in the smoking tobacco compositions and in the smoking tobacco article components.
Arctander "Perfume and Flavor Chemicals (Aroma Chemicals)" Volume II, published by the author 1969 discloses at Monograph 1932, ten-carbon atom containing alkylidene methyl cycloalkenones, specifically, 3-methyl-5-n-butylidene cyclopenten-2-one defined according to the structure: ##STR3## Arctander describes this compound as having a warm, caramellic, fruity odor reminiscent of strawberry; a sweet, fruity "cooked" strawberry flavor in dilutions below 20 ppm; and indicates that the ketone has been used and is "still used" to some extent in flavor compositions, rarely in perfumes. Arctander further states that this compound could be used as a modifier in fruity, floral bases since it blends excellently with the jasmone derivatives and isomers and also with the ionones.
Although substituted alkyl isopropyl cyclohexenones are known in the prior art, the disclosure of these substituted alkyl isopropyl cyclohexenones does not include the utilization thereof in perfumery and, furthermore, does not include processes for producing the substituted alkyl isopropyl cyclohexenones of our invention. Thus, Wiemann, et al and Riand and Brun in the references:
disclose the compounds having the structures: ##STR4## produced by dimerization of the compound having the structure: ##STR5## over magnesium oxide dimerization catalyst in the gas phase according to the reaction: ##STR6##
The prior art process of Riand and Brun or Wiemann, et al does not utilize a liquid phase dimerization and does not utilize the catalyst systems of our invention. Thus, the reaction mixture produced by Riand and Brun or Wiemann does not give rise to the same mixture of compounds as our invention and, furthermore, carrying out the process of our invention, we produce certain novel compounds not heretofore produced.
Unsaturated cyclic ketones with unsaturated alkylene and alkylidene side chains are known in the field of perfumery but these compounds are different in kind in structure from the structures of the compounds of the present invention. Thus, piperitenone having the structure: ##STR7## is disclosed by Arctander, "Perfume and Flavor Chemicals (Aroma Chemicals)" at Monograph No. 2628 to have a powerful, sharp, minty, bitter-herbaceous odor of moderate intensity. Arctander further states at Monograph No. 2629 that isopiperitenone having the structure: ##STR8## has a powerful, diffusive odor sweeter than that of piperitenone but equally minty, penetrating and of moderate tenacity. At Monograph No. 579, Arctander describes d-carvone having the structure:. ##STR9##